The following table summarizes the yields to maturity on several one-year, zero-coupon securities:

Security	Yield
Treasury	3.11%
AAA corporate	3.16%
BBB corporate	4.25%
B corporate	4.88%

.

(Note:

The yields displayed in the table are annually compounded yields.)

a. What is the price (expressed as a percentage of the face value) of a one-year, zero-coupon corporate bond with an AAA rating?

b. What is the credit spread on AAA-rated corporate bonds?

c. What is the credit spread on B-rated corporate bonds?

d. How does the credit spread change with the bond rating? Why?